Measure the surface area of parsed triangle meshes and review a conditional volume estimate when basic shell checks pass. Choose explicit units and inspect the model locally.
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Measure the triangles. Understand the volume limits.Local analysis · no uploads
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Supported triangle meshes: STL, OBJ, PLY, static GLB/glTF 2.0, plain OFF, 3DS and legacy VTK POLYDATA. Select local BIN companions with glTF. Up to 20 MiB per file, 40 MiB total and 100,000 triangles. Point clouds, lines and mixed primitive models are rejected.
Choose a mesh to begin.
No physical units are assumed.
Settings change displayed values only. They do not transform the mesh. No weight or material density is inferred.
Parsed mesh measurements
No source loaded.
Triangle surface area
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source units²
Conditional volume estimate
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source units³
Volume is reported only when the basic shell checks pass, with additional untested assumptions stated.
Area sums all parsed faces, including overlaps, duplicate faces and interior surfaces. It is not the area of a repaired or boolean-unioned solid.
A local 3D preview will appear here. Measurements do not require WebGL; the preview does.
Orbit, zoom and fullscreen affect only the view. All parsed triangles remain included in measurements.
Mesh checks and calculation notes
Vertices match by exact parsed coordinates, with no tolerance welding. The shell gate checks edge incidence, two-face winding, duplicate/zero-area faces, one vertex-connected component, and connected face fans at every vertex. It does not detect self-intersections, overlapping geometry, nesting, hidden cavities, wall thickness or printability. A conditional volume is the absolute signed tetrahedral integral, not certified material volume. Original file normals are ignored. Source parser precision and omissions remain relevant.
Reference: CGAL mesh-processing documentation distinguishes geometric measures, orientation and intersection checks. This tool uses its own bounded local calculations; it does not embed CGAL or claim equivalent validation.
A FEW SIMPLE STEPS
How to use 3D Surface Area & Volume
Choose a supported triangle mesh with its local glTF BIN companions if needed, or try the closed/open examples.
Review the calculated triangle area, conditional-volume status and shell diagnostics. Preview controls do not change the measured geometry.
For a known physical scale, state what one coordinate unit represents and choose output units. Other formats start unknown; glTF defaults to metres.
Adjust significant digits, then copy the measurements with their conditions or download the full JSON report.
PRIVATE BY DESIGN
Why use this tool?
Models never leave your device. Geometry parsing, measurements, shell checks and previews use self-hosted code in your browser. Measurements and reports can work even without WebGL; WebGL 2 is needed only for the interactive preview.
Tool inputs stay in your browser. Only your theme preference is saved on this device.
A few things worth knowing
Why is volume sometimes not reported?
Volume is withheld when basic edge, winding, duplicate/degenerate-face checks fail, when there are multiple components, when a vertex has disconnected face fans, or when the signed integral is numerically unreliable. The tool does not repair or merge solids. Open surfaces can still have a triangle-area sum.
Does a conditional volume mean the mesh is valid?
No. It assumes a single embedded shell without self-intersections or overlapping geometry. Intersections, nesting, hidden cavities, wall thickness and printability are not tested. Even when the basic checks pass, this is a qualified signed-integral estimate rather than certified material volume. Globally reversed winding is handled with an absolute volume; the signed value remains in the report.
Is surface area the exterior area of the solid?
It is the sum of all parsed triangle areas, including duplicated, overlapping and interior faces. It is not exterior-area extraction or the area of a boolean union. Source parser omissions and triangulation approximations remain relevant.
How are units and precision handled?
No physical size is inferred for unknown sources. Explicitly choose millimetres, centimetres, metres, inches or feet for one model coordinate unit; glTF uses its metre convention by default. Display-unit changes scale area by the square and volume by the cube of the length ratio. They do not transform the model. Calculations are floating-point approximations; significant digits control display only.
Which files and limits are supported?
The supported triangle subset of STL, OBJ, PLY, static GLB/glTF 2.0, plain OFF, 3DS and legacy VTK POLYDATA. Select local BIN companions with glTF. Maximum 20 MiB per file, 40 MiB total and 100,000 triangles, with bounded analysis and preview timeouts. Lines, point clouds and mixed primitive models are rejected; no remote assets are loaded.
